Qt5

Question

我正在尝试将 qDebug() 语句的结果传递到 QTextEdit 但没有成功，因为我遇到了 'This' cannot be implicitly captured in this context 的编译器错误，而且我从未遇到过此错误之前。

然后在执行 QProcess 后输出，并想在 QTextEdit 上显示它，我有以下内容：

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    startLidar();
    ui->textEditLidar->setText("[STATUS] NO PROCESS STARTED: ");
    ui->textEditGUI->setText("[STATUS] NO PROCESS STARTED: ");
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::startLidar()
{
    // Execution of the QProcess to make sure Lidar App Launcher opens:
    this->executeROSLidarApp = new QProcess(this);
    this->executeROSLidarApp->setProcessChannelMode(QProcess::MergedChannels);
    connect(this->executeROSLidarApp, QOverload<int, QProcess::ExitStatus>::of(&QProcess::finished),
            [script = this->executeROSLidarApp](int exitCode, QProcess::ExitStatus exitStatus){
            qDebug() << "[EXEC] FINISHED: " << exitCode << exitStatus;
            if(script->bytesAvailable() > 0) qDebug() << "[EXEC] buffered DATA:" << script->readAll();

            ui->textEditLidar->setText("would like to see the output of the exitCode and exitStatus"); // <-- error here

    });
    connect(this->executeROSLidarApp, &QProcess::errorOccurred, [script = this->executeROSLidarApp](QProcess::ProcessError error) {
            qDebug() << "[EXEC] error on execution: " << error << script->errorString();

            ui->textEditLidar->setText("would like to see the output of the error"); // <-- error here
    });
}

我认为这与我使用的不同 C++ 版本有关。我一直在使用 C++11，它似乎与一个可能的 lambda 函数编译错误有关。我一直在努力研究这个错误并发现了 , 来源，一切似乎都导致了不同版本之间的不匹配。如果需要，我还可以包含我的 .pro 文件。

感谢您阐明这个问题，并指出解决这个问题的正确方向。

Answer 1

你的 lambda 没有捕捉到它（正如错误消息告诉你的那样）但你正在尝试访问它（ui->textEditLidar->...）

Answer 2

您的 lambda 不捕获 ui 或 this，因此无法调用 ui->textEditLidar->setText。

改变这个

connect(this->executeROSLidarApp, &QProcess::errorOccurred, [script = this->executeROSLidarApp](QProcess::ProcessError error) {
        qDebug() << "[EXEC] error on execution: " << error << script->errorString();

        ui->textEditLidar->setText("would like to see the output of the error"); // <-- error here
});

至此

connect(this->executeROSLidarApp, &QProcess::errorOccurred, [this, script = this->executeROSLidarApp](QProcess::ProcessError error) {
        qDebug() << "[EXEC] error on execution: " << error << script->errorString();

        ui->textEditLidar->setText("would like to see the output of the error"); // <-- error here
});

或这个

connect(this->executeROSLidarApp, &QProcess::errorOccurred, [ui, script = this->executeROSLidarApp](QProcess::ProcessError error) {
        qDebug() << "[EXEC] error on execution: " << error << script->errorString();

        ui->textEditLidar->setText("would like to see the output of the error"); // <-- error here
});

Qt5 - C++11：'This' 无法在此上下文中隐式捕获

Qt5 - C++11: 'This' cannot be implicitly captured in this context

c++

qt

qtextedit

c++11